This invention relates in general to indicating apparatus and more particularly, to an indicating apparatus for use in a multi-zone intrusion system.
There is in existance many different intrusion systems which operate to monitor premises and to transmit suitable warnings for the occurrence of a break-in attempt, such as burglary or to monitor other conditions, such as fire, smoke and so on. Such systems have been generally referred to as intrusion systems and essentially provide an alarm when an unauthorized condition exists on the premises being monitored.
In regard to such systems as presently employed, a central alarm may monitor many zones associated with a given location. For example, in a factory or office complex, a central alarm may be used to indicate an unauthorized condition which exists in one or more locations. It is of course an object of such a central alarm system to indicate to the user which of the particular zones is associated with the unauthorized condition. As such, such systems have an alarm panel to which each zone is connected to indicate the status of the same.
In most present systems each zone would be associated with a separate lamp or other indicator which operates to designate to the user the location of the intrusion. Hence, according to such systems, a separate lamp or other indicator would be necessary to provide an indication for each zone which is being protected by the system. The same panel is also utilized to secure the premises during periods when they are not occupied. Hence, the alarm panel is also used or employed to assure that all zones are intact and therefore have no undesirable instrusion before the system is armed or activated for protection. In many systems a separate number of indicators such as lamps are used to indicate this condition. Hence, as one can see, an alarm panel employed in a multi-zone alarm system can constitute a large number of separate indicating devices each associated with a separate zone being monitored by the system.
It is of course understood that such systems can be expensive due to the large number of indicators, as well as consuming a great deal of power which is necessary to actuate the indicating devices.
The prior art has provided various means for utilizing indicators to distinguish one zone from another. For example, U.S. Pat. No. 3,150,359 entitled Remote Alarm Indicator issued on Sept. 22, 1964 to P. J. Hoey shows a system where any one of a number of different alarm conditions are indicated by separate lamps. In this system each lamp is associated with a separate flashing unit and the operator at the central station or at the alarm panel can determine the particular alarm condition by timing the flashing rate of the lamp.
In other systems such as shown in U.S. Pat. No. 4,103,298 entitled Alarmed Device issued on July 25, 1978 to R. J. Redding, there is described an indicator system which uses different flashing rates to distinguish different alarm conditions.
Other patents such as U.S. Pat. No. 3,757,323 entitled DC Monitoring System Using Two Wire Transmission Lines issued on Sept. 4, 1973 to R. H. Pintell, relate to the use of indicating lamps to determine different alarm conditions during system operation. Still other patents depict various signaling techniques used for various purposes as to reduce power consumption and so on. Example of such patents are U.S. Pat. No. 4,124,842 and U.S. Pat. No. 4,211,956.
In any event, there is a need for a system which is capable of displaying and annunciating an undesirable condition in anyone of a plurality of monitored zones which uses a single indicator as a display. The system thus provided results in a savings in components, as well as a savings in power, in that it uses a single indicator to provide an indication of the zone location which is subjected to an unauthorized intrusion.